Summary:This is a retrospective cohort study to compare clinical outcomes of patients with osteomyelitis who received initial antibiotics to target MRSA versus those who received MSSA-only coverage. Clinical outcomes included hospital readmission rates, repeat MRI, and improvement in inflammatory markers (WBC and CRP) within a 72-hour period.​ · Repeat MRI was more frequent in the MRSA coverage group compared to the MSSA-only coverage group, both within 7 days (8.6% vs 4.1%) and within 180 days (12% vs 5.8%). · Hospital readmission rates were similar between both groups. · Patients had similar rates of CRP normalization within a 72-hour period. · The MRSA coverage group had a lower rate of WBC normalization compared to the MSSA-only coverage group (4.2% vs 16.4%).

Key strengths of the article: This is a novel study with potential for significant implications, especially given osteomyelitis is a relatively common diagnosis and the importance of antimicrobial stewardship. The study included multiple centers with wide geographic variability. It also used a combination of lab and radiographic data. Physician validation of data was employed, therefore increasing reliability of results.

Key limitations: The study’s design is vulnerable to confounding by indication. There is potential for increased virulence of MRSA compared to MSSA, therefore the results of the study are potentially reflective of local MRSA prevalence rather than the choice of empiric therapy. Also, patients who received any MRSA coverage were included in the MRSA group, even if they received MSSA-only coverage the majority of the time.

​Major takeaway: This is primarily a hypothesis generating study. It raises the importance of the need for further studies regarding empiric treatment for osteomyelitis.

How this article should impact our practice: Further research studies are need prior to implementing change. If future studies replicate these finding, we will need to re-evaluate empiric therapy for osteomyelitis.